Re: simple point function seems strange
Posted by
Henrik Sperre Johansen on
Jul 07, 2010; 10:28pm
URL: https://forum.world.st/simple-point-function-seems-strange-tp2281587p2281610.html
On 08.07.2010 00:26, Henrik Sperre Johansen wrote:
> On 08.07.2010 00:11, Stéphane Ducasse wrote:
>> Hi
>>
>> (10@20) rotateBy: #left centerAt: 0 @0
>> returns
>> 20@ -10
>>
>> and my math tells me that this is a rotation to the right.
>>
>> Am I correct?
>> Then why I'm wrong? screen coordinates vs. math coordinate?
>>
>> Stef
> You rotate around the center, left is compared to the center -> point
> vector, not the other way around.
>
> Cheers,
> Henry
... assuming you use screen coordinates of course, starting at top left :)
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